Brief overview of Seismic designs for masonry building

The National Building Code of Canada 2005 (NBCC 2005) and the CSA S304.1-04 masonry design standard are two useful construction documents which facilitate the structural engineers to create design for masonry buildings toward seismic load effects.

This article offers a explanation on the elementary theoretical background and theory for the CSA S304.1-04 seismic design provisions. Modifications in the seismic design provisions are described in Part 4 of the NBCC 2005 and CSA S304.1-04, as well as how these affect the masonry design and construction.

This document provides a detailed up-to-date guide on seismic design and building of masonry structural elements for low to mid-rise structures, like warehouses, industrial buildings, schools, commercial buildings, and residential/hotel structures. This construction article mainly focuses on how to apply concrete block units for designing and construction of masonry structures.

Learn the use of seismic design provisions and cross-referencing of code clauses for designers. The addendums consist of some helpful documentations like design processes and research background toward some of the design provisions. The applicable code clauses are provided through framed boxes wherever required.

Chapter 1 offers the assessment of the general seismic design provisions described in Part 4 of NBCC 2005, together with seismic hazard levels, and the relevent static force processes. One can learn the primary design parameters which range from irregularities, torsion, height limitations, and the ductility and overstrength features for masonry structures. Besides, there is an explanation to the dynamic analysis of structures to simplify the suitable code provisions. As lots of updates are made to the seismic provisions in NBCC 2005, relevancies with the earlier 1995 edition of the building code are also provided in Appendix A.

Chapter 2 contains an explanation of seismic design needs for reinforced masonry walls. Applicable CSA S304.1-04 design needs are provided together with concerned commentary having brief interpretation concerning code provisions. Here topics covered reinforced masonry shear walls based on in-plane and out-of-plane seismic loads, as well as a eloborate explanation of the CSA S304.1 seismic design needs. Some exclusive topics like masonry infill walls, stack pattern walls, masonry veneers, and construction-related issues are also covered. Amendments in CSA S304.1-04 seismic design needs from the earlier (1994) edition are explained and discussed,together with their design suggestions. Appendix B includes topics associated with the Chapter 2 content which range from findings of research studies and foreign code provisions concerning seismic design of masonry structures.

Chapter 3 sum ups differentiations in seismic design provisions explained in the 1995 and 2005 editions of NBCC, and the 1994 and 2004 editions of CSA S304.1. Designers having ideas on the brief seismic and masonry design problems naratted in Chapters 1 and 2, can shift directly to this summary chapter. The differentiations in code provisions are explained in a tabular format. This chapter also synopsizes the viii results of a case study concerning a typical warehouse building designed following NBCC 1995 and NBCC 2005. This construction artilce also focus on three Canadian locationsdefined by various seismic hazards (Vancouver, Calgary, and Toronto).

Chapter 4 offers explanatory design instances of seismic load estimates and allocation of forces to members as per NBCC 2005, and the design of loadbearing and nonloadbearing masonry elements to CSA S304.1-04. The outline of masonry buildings and the mechanical characteristics of their components in the examples are provided to cope up with the circumstances often faced in design practice, specifically when these associated with the torsionally unsymmetric buildings. These explanations set out in a progressive manner, involving adequate examples and proper demonstrations required to modify the design process. Appendix C offers related background information toward the design examples, along with an comprehensive discussion of in-plane wall stiffness. Appendix D offers design assistances applied in the Chapter 4 examples.